Powder-based polymer processes part1 Flashcards
Powder-based processes
Apart from Z-printing (which isn’t actually powber - but it is in the same category) , give two other examples of this process:
- Laser Sintering
- High Speed Sintering (in process of commercialisation)
Course information
no unanimous agreement on classification of systems
• For this module the processes have split by generic ……….. type
e.g ……../ ………… / ……………
• Then grouped by ‘………..’ processes
• Important thing is to understand the processes &
their …………….
material
polymers /metals/ others
similar
applications
Z - Printing
19…. - core technology developed at MIT
• ……….. the technology to a number of companies
for different ………../…………
• In this lecture, focus is on plaster/………. based
materials
• (Similar process also used for metals & …………. )
1993
Licensed
applications/materials
starch
ceramics
Z- Printing Background
Originally known as ‘….. ………..’ – at the time,this term was specific to this particular process
• Technology licensed to ..-…………. for
production of commercial systems
• 3D Systems recently
took over Z-Corporation.
• Re-branded as ‘..-……….’
3d printing
Z-Corporation
Z-Printing
Z-Printing
give the definition of Z-printing
Layer-by-layer approach to
selectively bind and adhere layers
of powder to form a solid object’
Z-Printing Process
Uses an …. -…. printhead to deposit a ……… (…….)
onto the required ……..-………..
Ink-Jet
binder(glue)
Cross-section
For more information see
http://www.zcorp.com/documents/108_3D%20Printing%20White%20Paper
%20FINAL.pdf
(Just bear in mind this is a sales pitch…)
Z-Printing Process
Describe the process in 3 stages
- Deposit a layer of powder
- Print cross-section
- Drop platform by one layer & deposit next layer of powder
Z- Printinig process
• Fill powder supply area with ……… …………
• Check and/or replace binder …………
• Import ….. …….. & add ………. if relevant
• Deposit layer of powder from powder supply area
• Print binder onto ……..-……….
• Lower ……… …. ……… by one layer
• Raise ………… ………… …….. & deposit next layer of
powder
• Remove part from powder ‘………’
• …….-………….
loose powder
cartridge
.stl file , colour
cross-section
powder bed piston
powder delivery piston
cake
post-processing
Z- Printing post processing
• ………/……… away loose powder (gently!)
• This leaves you with a ‘…….’ part which is
relatively …….. and ………
• Often ……… (e.g. with wax/epoxy) to give the part ……… and ………. …………
vacuum/wash
green
weak, porous
infiltrate , strength
colour vividness
Advantage of Z-Printing
Give 5 advantages of this process
1) Office-friendly
• Low heat, noise etc.
2) Ease of use
• Does not require large amounts of training
• E.g. easier to use for whole design team
3)Speed – use of ink-jet technology allows
relatively fast printing of build volume
4) System & material costs relatively low
5) Can print full-scale colour!
What are 3 disadvantages of Z-Printing?
1) Weakness of ‘green’ part
• Can lead to damage during clean-up
• Limitations on thin features
2) Generally low mechanical properties
• Compared with other AM processes
3) Only surface colour
Applications of Z-Printing
• Most often used for ………… models, rather
than ………… parts
• Many of its main uses are a direct result of ability
to produce ………… parts
give 4 examples :
visualisation
structural
coloured
- Architectural models
- Consumer/ergonomic trials
- Finite Element models
- Medical applications (developing)
Architectural Models - Z-Printing
give 4 reasons why this method is used for architectural models :
1)Often one-off models
• Cost & time savings, especially over hand-crafting
2) Much easier visualisation than 2D plans, or even
a 3D CAD model
• E.g. to inform the General Public
• Tendering processes
3) Detail
• E.g. people, trees, etc.
4) Colour
• Benefit over other AM!
Customer trials , Z-Printing
Give 2 reasons why you would use Z-printing for this :
1) The ability to trial a product
before beginning production can be invaluable
• Establish customer opinions before it’s too late!
2) Colour is a real benefit here
• Enhanced realism
• Colour preferences?
Finite Element models , Z-Printing
What is the reason to use Z-printing for these models ?
You can apply FEA stress plot to surface of part
• Useful for visualisation & to aid in re-design process
• Can extend this to testing – does your part fail in the
same place as your model predicts?
• Consumer use – looks ‘a bit sciencey’
Medical Models , Z-Printing
What is a reason for using this process for these models?
E.g. surgical practice:
• Reproduce similar visual appearance
• Similar ‘feel’ – different materials/binders?
• Appearance during 3D imaging
http://www.lboro.ac.uk/research/view/
aw09/articles/sinus-surgery.html
Laser Sintering - Background
Process patented by Ross Householder in 19…
Carl Deckard (University of Texas) continued this work
• First commercial machine produced by DTM
Corporation in 19…
• The course focus is on polymer materials (Similar process also used for metals & other materials)
1979
1992
Laser Sintering - Process
• Parts built by ………… scanning and sintering
…….-………… of powdered material
• Normally conducted in a ……… atmosphere for 2 reasons:
- …….
- ………..
selectively
cross-section
nitrogen
safety
oxidation
Laser Sintering - Process
- Fill powder supply area with ………. powder
- ….-……… powder (and sometimes feed area)
- Import … …… & ……/orientate parts
- Deposit layer of powder from powder …….. ……
- Scan cross-section with …. laser
- Lower powder … ….. by one layer
- Raise powder ……. ….. & deposit next powder layer
- …..-…..
- Remove part from powder ‘…….’
- ……-……….
loose
pre-heat
.stl file , nest
supply area
CO2
bed piston
delivery piston
cool-down
cake
post-process
Laser-Sintering , Post processing
Brush away ……. ………
• This leaves you with ‘………’ part
• Common to ……-……. parts to remove
remaining powder/improve …….. ……..
• Depending on ………. – un-used powder can
be …….. to an extent
loose powder
completed
bead blast
surface finish
material
recycled
Lasering Sintering - Advantages
give 4 advantages of this process:
1) No support structures (polymers)
2) Allows more complex designs
• Assemblies produced as one
• Less post-processing required
• Time-saving
• Better surface finish on down-facing surfaces
3) Relatively high mechanical properties & stability
of properties
4) Build through build volume (not area)
Laser Sintering - Disadvantages
give 6 disadvantages of this process:
1) Surface finish of parts
2) Speed of process
• Set-up and pre-heat
• Laser scan time for large cross-sections
3) Material changeover on older systems
4) Warpage of parts
5) Mechanical properties affected by thermal
variations
6) Powder can have health & safety issues
Laser Sintering ,Materials 1
• Mainly …… -based (large processing window)
- A range of properties are achieved by inclusion of …….
(e.g. ……….., …….., ……..-…….) - Some other materials are used (e.g. …………., TPU)
- Large overlap in range of materials for EOS and 3D
Systems, and a few other material suppliers, e.g. Solid
Concepts, CRP Technology, ALM
• Major global manufacturers becoming interested…
- Will …….. range of available materials
-……. costs (currently … x the cost of similar, non-AM
materials)
nylon
fillers
aluminium, glass, carbon-fibre
poly-propylene
broaden
lower
10
Laser Sintering , Materials 2
• Large amount of ……… in new materials
- E.g. …………. (rubber-like materials)
- ….. ………. materials (e.g. PEEK)
- ……….materials
- Bio-compatibility
- Ability to be ……… - Wider range of ………… (e.g. flame retardancy)
• New materials often tend to be as a result of
new industry …………..
interest
elastomers
high performance
Medical
sterilised
properties
requirements
